Analysis of Scattering and Absorption Characteristics of Metal Powder Layer for Selective Laser Sintering

A modified sequential addition method is proposed for simulating the deposition of the metal powder layers used in selective laser sintering (SLS) process. The scattering characteristics of the deposited layers are analyzed by means of Monte Carlo ray-tracing simulations and a gray-level co-occurrence matrix (GLCM) method. The validity of the proposed modeling approach is demonstrated by comparing simulation results for the gray-scale properties of the scattered image and the absorption coefficient of the metal powder layer with the experimental results obtained using a scanned laser pico-projection (SLPP) detection method and the simulation findings presented in the literature, respectively. Further simulations are then performed to investigate the effect of the metal powder packing density on the scattering characteristics and absorption of metal powder layers. The results show that a higher packing density leads to a lower scattering effect and a greater absorptivity. In addition, as compared with the characteristics of scattering and absorption of metal powder layers with different size distributions, it is shown that a bimodal distribution of the powder particle size results in the lowest scattering effect and the highest absorptivity given an appropriate specification of distribution parameters for powder structures used in SLS.